Brian Steinberg Senior TV EditorFanDuel spends hundreds of thousands of dollars on commercials that surround big sports broadcasts. Now it wants to make sports-wagering — the activity at the core of its business — a bigger part of the studio discussions that are also such an essential part of the sports-TV experience.Charles Barkley, one of the standouts on the analyst roster on the “NBA on TNT” show, has agreed to work as an ambassador and spokesman for the sports-betting giant.